1. Field of the Invention
The present invention relates to a method of determining the validity of service announcements as well as to a corresponding system and user entity.
2. Related Background Art
The work to standardize a multimedia broadcast/multicast service (MBMS) has been started in the 3rd Generation Partnership Project (3GPP). One of the aims of the work has been to introduce a service provision scheme, which allows multiple subscribers to receive a common transmission through the air interface simultaneously. This transmission may for instance contain video clips from news, sport events, etc.
The multimedia broadcast/multicast services (MBMS) are available within a broadcast/multicast service area (SA), which is defined individually per broadcast/multicast service. That is, a service area is defined as an area where a specific broadcast/multicast service is available, i.e. every area where a specific broadcast/multicast service is available is part of the corresponding service area. Such a service area may comprise one or more local areas which is/are that/those area(s) where the service content is the same. The broadcast/multicast service area may represent the coverage area of an entire Public Land Mobile Network (PLMN), or part(s) of the Public Land Mobile Network's coverage area.
In each cell, service announcements need to be transmitted thus allowing the user to discover the subscribed broadcast/multicast services that are currently active or that will become active at some time later, either at the user's current location or at some other location. These service announcements are identical in those cells where an identical set of services is offered.
However, if a user entity (UE) has to check the service announcement every time it enters a new cell, the battery life of the user entity (UE) may be considerably reduced in relation to such a standard action, since the service announcement can be quite lengthy.